1 /* $NetBSD: rcmd.c,v 1.59 2005/03/30 16:12:58 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1983, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char sccsid[] = "@(#)rcmd.c 8.3 (Berkeley) 3/26/94"; 36 #else 37 __RCSID("$NetBSD: rcmd.c,v 1.59 2005/03/30 16:12:58 christos Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #ifdef _LIBC 42 #include "namespace.h" 43 #endif 44 #include <sys/param.h> 45 #include <sys/socket.h> 46 #include <sys/stat.h> 47 #include <sys/poll.h> 48 #include <sys/wait.h> 49 50 #include <netinet/in.h> 51 #include <rpc/rpc.h> 52 #include <arpa/inet.h> 53 #include <netgroup.h> 54 55 #include <assert.h> 56 #include <ctype.h> 57 #include <err.h> 58 #include <errno.h> 59 #include <fcntl.h> 60 #include <grp.h> 61 #include <netdb.h> 62 #include <paths.h> 63 #include <pwd.h> 64 #include <signal.h> 65 #include <stdio.h> 66 #include <stdlib.h> 67 #include <string.h> 68 #include <syslog.h> 69 #include <unistd.h> 70 71 #include "pathnames.h" 72 73 int orcmd __P((char **, u_int, const char *, const char *, const char *, 74 int *)); 75 int orcmd_af __P((char **, u_int, const char *, const char *, const char *, 76 int *, int)); 77 int __ivaliduser __P((FILE *, u_int32_t, const char *, const char *)); 78 int __ivaliduser_sa __P((FILE *, struct sockaddr *, socklen_t, const char *, 79 const char *)); 80 static int rshrcmd __P((char **, u_int32_t, const char *, const char *, 81 const char *, int *, const char *)); 82 static int resrcmd __P((struct addrinfo *, char **, u_int32_t, const char *, 83 const char *, const char *, int *)); 84 static int __icheckhost __P((struct sockaddr *, socklen_t, const char *)); 85 static char *__gethostloop __P((struct sockaddr *, socklen_t)); 86 87 int 88 rcmd(ahost, rport, locuser, remuser, cmd, fd2p) 89 char **ahost; 90 u_short rport; 91 const char *locuser, *remuser, *cmd; 92 int *fd2p; 93 { 94 95 return rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET); 96 } 97 98 int 99 rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af) 100 char **ahost; 101 u_short rport; 102 const char *locuser, *remuser, *cmd; 103 int *fd2p; 104 int af; 105 { 106 static char hbuf[MAXHOSTNAMELEN]; 107 char pbuf[NI_MAXSERV]; 108 struct addrinfo hints, *res; 109 int error; 110 struct servent *sp; 111 112 _DIAGASSERT(ahost != NULL); 113 _DIAGASSERT(locuser != NULL); 114 _DIAGASSERT(remuser != NULL); 115 _DIAGASSERT(cmd != NULL); 116 /* fd2p may be NULL */ 117 118 snprintf(pbuf, sizeof(pbuf), "%u", ntohs(rport)); 119 memset(&hints, 0, sizeof(hints)); 120 hints.ai_family = af; 121 hints.ai_socktype = SOCK_STREAM; 122 hints.ai_flags = AI_CANONNAME; 123 error = getaddrinfo(*ahost, pbuf, &hints, &res); 124 if (error) { 125 warnx("%s: %s", *ahost, gai_strerror(error)); /*XXX*/ 126 return (-1); 127 } 128 if (res->ai_canonname) { 129 /* 130 * Canonicalise hostname. 131 * XXX: Should we really do this? 132 */ 133 strlcpy(hbuf, res->ai_canonname, sizeof(hbuf)); 134 *ahost = hbuf; 135 } 136 137 /* 138 * Check if rport is the same as the shell port, and that the fd2p. If 139 * it is not, the program isn't expecting 'rsh' and so we can't use the 140 * RCMD_CMD environment. 141 */ 142 sp = getservbyname("shell", "tcp"); 143 if (sp != NULL && sp->s_port == rport) 144 error = rshrcmd(ahost, (u_int32_t)rport, 145 locuser, remuser, cmd, fd2p, getenv("RCMD_CMD")); 146 else 147 error = resrcmd(res, ahost, (u_int32_t)rport, 148 locuser, remuser, cmd, fd2p); 149 freeaddrinfo(res); 150 return (error); 151 } 152 153 /* this is simply a wrapper around hprcmd() that handles ahost first */ 154 int 155 orcmd(ahost, rport, locuser, remuser, cmd, fd2p) 156 char **ahost; 157 u_int rport; 158 const char *locuser, *remuser, *cmd; 159 int *fd2p; 160 { 161 return orcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET); 162 } 163 164 int 165 orcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af) 166 char **ahost; 167 u_int rport; 168 const char *locuser, *remuser, *cmd; 169 int *fd2p; 170 int af; 171 { 172 static char hbuf[MAXHOSTNAMELEN]; 173 char pbuf[NI_MAXSERV]; 174 struct addrinfo hints, *res; 175 int error; 176 177 _DIAGASSERT(ahost != NULL); 178 _DIAGASSERT(locuser != NULL); 179 _DIAGASSERT(remuser != NULL); 180 _DIAGASSERT(cmd != NULL); 181 /* fd2p may be NULL */ 182 183 snprintf(pbuf, sizeof(pbuf), "%u", ntohs(rport)); 184 memset(&hints, 0, sizeof(hints)); 185 hints.ai_family = af; 186 hints.ai_socktype = SOCK_STREAM; 187 hints.ai_flags = AI_CANONNAME; 188 error = getaddrinfo(*ahost, pbuf, &hints, &res); 189 if (error) { 190 warnx("%s: %s", *ahost, gai_strerror(error)); /*XXX*/ 191 return (-1); 192 } 193 if (res->ai_canonname) { 194 strlcpy(hbuf, res->ai_canonname, sizeof(hbuf)); 195 *ahost = hbuf; 196 } 197 198 error = resrcmd(res, ahost, rport, locuser, remuser, cmd, fd2p); 199 freeaddrinfo(res); 200 return (error); 201 } 202 203 /*ARGSUSED*/ 204 static int 205 resrcmd(res, ahost, rport, locuser, remuser, cmd, fd2p) 206 struct addrinfo *res; 207 char **ahost; 208 u_int32_t rport; 209 const char *locuser, *remuser, *cmd; 210 int *fd2p; 211 { 212 struct addrinfo *r; 213 struct sockaddr_storage from; 214 struct pollfd reads[2]; 215 sigset_t nmask, omask; 216 pid_t pid; 217 int s, lport, timo; 218 int pollr; 219 char c; 220 int refused; 221 222 _DIAGASSERT(res != NULL); 223 _DIAGASSERT(ahost != NULL); 224 _DIAGASSERT(locuser != NULL); 225 _DIAGASSERT(remuser != NULL); 226 _DIAGASSERT(cmd != NULL); 227 /* fd2p may be NULL */ 228 229 r = res; 230 refused = 0; 231 pid = getpid(); 232 sigemptyset(&nmask); 233 sigaddset(&nmask, SIGURG); 234 if (sigprocmask(SIG_BLOCK, &nmask, &omask) == -1) 235 return -1; 236 for (timo = 1, lport = IPPORT_RESERVED - 1;;) { 237 s = rresvport_af(&lport, r->ai_family); 238 if (s < 0) { 239 if (errno == EAGAIN) 240 warnx("rcmd: socket: All ports in use"); 241 else 242 warn("rcmd: socket"); 243 if (r->ai_next) { 244 r = r->ai_next; 245 continue; 246 } else { 247 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 248 return (-1); 249 } 250 } 251 fcntl(s, F_SETOWN, pid); 252 if (connect(s, r->ai_addr, r->ai_addrlen) >= 0) 253 break; 254 (void)close(s); 255 if (errno == EADDRINUSE) { 256 lport--; 257 continue; 258 } else if (errno == ECONNREFUSED) 259 refused++; 260 if (r->ai_next) { 261 int oerrno = errno; 262 char hbuf[NI_MAXHOST]; 263 const int niflags = NI_NUMERICHOST; 264 265 hbuf[0] = '\0'; 266 if (getnameinfo(r->ai_addr, r->ai_addrlen, 267 hbuf, sizeof(hbuf), NULL, 0, niflags) != 0) 268 strlcpy(hbuf, "(invalid)", sizeof(hbuf)); 269 warnx("rcmd: connect to address %s", hbuf); 270 errno = oerrno; 271 perror(0); 272 r = r->ai_next; 273 hbuf[0] = '\0'; 274 if (getnameinfo(r->ai_addr, r->ai_addrlen, 275 hbuf, sizeof(hbuf), NULL, 0, niflags) != 0) 276 strlcpy(hbuf, "(invalid)", sizeof(hbuf)); 277 (void)fprintf(stderr, "Trying %s...\n", hbuf); 278 continue; 279 } 280 if (refused && timo <= 16) { 281 (void)sleep((unsigned int)timo); 282 timo *= 2; 283 r = res; 284 refused = 0; 285 continue; 286 } 287 (void)fprintf(stderr, "%s: %s\n", res->ai_canonname, 288 strerror(errno)); 289 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 290 return (-1); 291 } 292 lport--; 293 if (fd2p == 0) { 294 write(s, "", 1); 295 lport = 0; 296 } else { 297 char num[8]; 298 int s2 = rresvport_af(&lport, r->ai_family), s3; 299 socklen_t len = sizeof(from); 300 301 if (s2 < 0) 302 goto bad; 303 listen(s2, 1); 304 (void)snprintf(num, sizeof(num), "%d", lport); 305 if (write(s, num, strlen(num) + 1) != 306 (ssize_t) (strlen(num) + 1)) { 307 warn("rcmd: write (setting up stderr)"); 308 (void)close(s2); 309 goto bad; 310 } 311 reads[0].fd = s; 312 reads[0].events = POLLIN; 313 reads[1].fd = s2; 314 reads[1].events = POLLIN; 315 errno = 0; 316 pollr = poll(reads, 2, INFTIM); 317 if (pollr < 1 || (reads[1].revents & POLLIN) == 0) { 318 if (errno != 0) 319 warn("poll: setting up stderr"); 320 else 321 warnx("poll: protocol failure in circuit setup"); 322 (void)close(s2); 323 goto bad; 324 } 325 s3 = accept(s2, (struct sockaddr *)(void *)&from, &len); 326 (void)close(s2); 327 if (s3 < 0) { 328 warn("rcmd: accept"); 329 lport = 0; 330 goto bad; 331 } 332 *fd2p = s3; 333 switch (((struct sockaddr *)(void *)&from)->sa_family) { 334 case AF_INET: 335 #ifdef INET6 336 case AF_INET6: 337 #endif 338 if (getnameinfo((struct sockaddr *)(void *)&from, len, 339 NULL, 0, num, sizeof(num), NI_NUMERICSERV) != 0 || 340 (atoi(num) >= IPPORT_RESERVED || 341 atoi(num) < IPPORT_RESERVED / 2)) { 342 warnx("rcmd: protocol failure in circuit setup."); 343 goto bad2; 344 } 345 break; 346 default: 347 break; 348 } 349 } 350 351 (void)write(s, locuser, strlen(locuser)+1); 352 (void)write(s, remuser, strlen(remuser)+1); 353 (void)write(s, cmd, strlen(cmd)+1); 354 if (read(s, &c, 1) != 1) { 355 warn("%s", *ahost); 356 goto bad2; 357 } 358 if (c != 0) { 359 while (read(s, &c, 1) == 1) { 360 (void)write(STDERR_FILENO, &c, 1); 361 if (c == '\n') 362 break; 363 } 364 goto bad2; 365 } 366 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 367 return (s); 368 bad2: 369 if (lport) 370 (void)close(*fd2p); 371 bad: 372 (void)close(s); 373 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 374 return (-1); 375 } 376 377 /* 378 * based on code written by Chris Siebenmann <cks@utcc.utoronto.ca> 379 */ 380 /* ARGSUSED */ 381 static int 382 rshrcmd(ahost, rport, locuser, remuser, cmd, fd2p, rshcmd) 383 char **ahost; 384 u_int32_t rport; 385 const char *locuser, *remuser, *cmd; 386 int *fd2p; 387 const char *rshcmd; 388 { 389 pid_t pid; 390 int sp[2], ep[2]; 391 char *p; 392 struct passwd *pw, pwres; 393 char pwbuf[1024]; 394 395 _DIAGASSERT(ahost != NULL); 396 _DIAGASSERT(locuser != NULL); 397 _DIAGASSERT(remuser != NULL); 398 _DIAGASSERT(cmd != NULL); 399 /* fd2p may be NULL */ 400 401 /* What rsh/shell to use. */ 402 if (rshcmd == NULL) 403 rshcmd = _PATH_BIN_RCMD; 404 405 /* locuser must exist on this host. */ 406 if (getpwnam_r(locuser, &pwres, pwbuf, sizeof(pwbuf), &pw) != 0) { 407 warnx("rshrcmd: unknown user: %s", locuser); 408 return(-1); 409 } 410 411 /* get a socketpair we'll use for stdin and stdout. */ 412 if (socketpair(AF_LOCAL, SOCK_STREAM, 0, sp) < 0) { 413 warn("rshrcmd: socketpair"); 414 return (-1); 415 } 416 /* we will use this for the fd2 pointer */ 417 if (fd2p) { 418 if (socketpair(AF_LOCAL, SOCK_STREAM, 0, ep) < 0) { 419 warn("rshrcmd: socketpair"); 420 return (-1); 421 } 422 *fd2p = ep[0]; 423 } 424 425 pid = fork(); 426 if (pid < 0) { 427 warn("rshrcmd: fork"); 428 return (-1); 429 } 430 if (pid == 0) { 431 /* 432 * child 433 * - we use sp[1] to be stdin/stdout, and close sp[0] 434 * - with fd2p, we use ep[1] for stderr, and close ep[0] 435 */ 436 (void)close(sp[0]); 437 if (dup2(sp[1], 0) < 0 || dup2(0, 1) < 0) { 438 warn("rshrcmd: dup2"); 439 _exit(1); 440 } 441 if (fd2p) { 442 if (dup2(ep[1], 2) < 0) { 443 warn("rshrcmd: dup2"); 444 _exit(1); 445 } 446 (void)close(ep[0]); 447 (void)close(ep[1]); 448 } else if (dup2(0, 2) < 0) { 449 warn("rshrcmd: dup2"); 450 _exit(1); 451 } 452 /* fork again to lose parent. */ 453 pid = fork(); 454 if (pid < 0) { 455 warn("rshrcmd: second fork"); 456 _exit(1); 457 } 458 if (pid > 0) 459 _exit(0); 460 461 /* Orphan. Become local user for rshprog. */ 462 if (setuid(pw->pw_uid)) { 463 warn("rshrcmd: setuid(%lu)", (u_long)pw->pw_uid); 464 _exit(1); 465 } 466 467 /* 468 * If we are rcmd'ing to "localhost" as the same user as we are, 469 * then avoid running remote shell for efficiency. 470 */ 471 if (strcmp(*ahost, "localhost") == 0 && 472 strcmp(locuser, remuser) == 0) { 473 if (pw->pw_shell[0] == '\0') 474 rshcmd = _PATH_BSHELL; 475 else 476 rshcmd = pw->pw_shell; 477 p = strrchr(rshcmd, '/'); 478 execlp(rshcmd, p ? p + 1 : rshcmd, "-c", cmd, NULL); 479 } else { 480 p = strrchr(rshcmd, '/'); 481 execlp(rshcmd, p ? p + 1 : rshcmd, *ahost, "-l", 482 remuser, cmd, NULL); 483 } 484 warn("rshrcmd: exec %s", rshcmd); 485 _exit(1); 486 } 487 /* Parent */ 488 (void)close(sp[1]); 489 if (fd2p) 490 (void)close(ep[1]); 491 492 (void)waitpid(pid, NULL, 0); 493 return (sp[0]); 494 } 495 496 int 497 rresvport(alport) 498 int *alport; 499 { 500 501 _DIAGASSERT(alport != NULL); 502 503 return rresvport_af(alport, AF_INET); 504 } 505 506 int 507 rresvport_af(alport, family) 508 int *alport; 509 int family; 510 { 511 struct sockaddr_storage ss; 512 struct sockaddr *sa; 513 int salen; 514 int s; 515 u_int16_t *portp; 516 517 _DIAGASSERT(alport != NULL); 518 519 memset(&ss, 0, sizeof(ss)); 520 sa = (struct sockaddr *)(void *)&ss; 521 switch (family) { 522 case AF_INET: 523 #ifdef BSD4_4 524 sa->sa_len = 525 #endif 526 salen = sizeof(struct sockaddr_in); 527 portp = &((struct sockaddr_in *)(void *)sa)->sin_port; 528 break; 529 #ifdef INET6 530 case AF_INET6: 531 #ifdef BSD4_4 532 sa->sa_len = 533 #endif 534 salen = sizeof(struct sockaddr_in6); 535 portp = &((struct sockaddr_in6 *)(void *)sa)->sin6_port; 536 break; 537 #endif 538 default: 539 errno = EAFNOSUPPORT; 540 return (-1); 541 } 542 sa->sa_family = family; 543 s = socket(family, SOCK_STREAM, 0); 544 if (s < 0) 545 return (-1); 546 #ifdef BSD4_4 547 switch (family) { 548 case AF_INET: 549 case AF_INET6: 550 *portp = 0; 551 if (bindresvport(s, (struct sockaddr_in *)(void *)sa) < 0) { 552 int sverr = errno; 553 554 (void)close(s); 555 errno = sverr; 556 return (-1); 557 } 558 *alport = (int)ntohs(*portp); 559 return (s); 560 default: 561 /* is it necessary to try keep code for other AFs? */ 562 break; 563 } 564 #endif 565 for (;;) { 566 *portp = htons((u_short)*alport); 567 if (bind(s, sa, (socklen_t)salen) >= 0) 568 return (s); 569 if (errno != EADDRINUSE) { 570 (void)close(s); 571 return (-1); 572 } 573 (*alport)--; 574 if (*alport == IPPORT_RESERVED/2) { 575 (void)close(s); 576 errno = EAGAIN; /* close */ 577 return (-1); 578 } 579 } 580 } 581 582 int __check_rhosts_file = 1; 583 char *__rcmd_errstr; 584 585 int 586 ruserok(rhost, superuser, ruser, luser) 587 const char *rhost, *ruser, *luser; 588 int superuser; 589 { 590 struct addrinfo hints, *res, *r; 591 int error; 592 593 _DIAGASSERT(rhost != NULL); 594 _DIAGASSERT(ruser != NULL); 595 _DIAGASSERT(luser != NULL); 596 597 memset(&hints, 0, sizeof(hints)); 598 hints.ai_family = PF_UNSPEC; 599 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 600 error = getaddrinfo(rhost, "0", &hints, &res); 601 if (error) 602 return (-1); 603 604 for (r = res; r; r = r->ai_next) { 605 if (iruserok_sa(r->ai_addr, (int)r->ai_addrlen, superuser, 606 ruser, luser) == 0) { 607 freeaddrinfo(res); 608 return (0); 609 } 610 } 611 freeaddrinfo(res); 612 return (-1); 613 } 614 615 /* 616 * New .rhosts strategy: We are passed an ip address. We spin through 617 * hosts.equiv and .rhosts looking for a match. When the .rhosts only 618 * has ip addresses, we don't have to trust a nameserver. When it 619 * contains hostnames, we spin through the list of addresses the nameserver 620 * gives us and look for a match. 621 * 622 * Returns 0 if ok, -1 if not ok. 623 */ 624 int 625 iruserok(raddr, superuser, ruser, luser) 626 u_int32_t raddr; 627 int superuser; 628 const char *ruser, *luser; 629 { 630 struct sockaddr_in irsin; 631 632 memset(&irsin, 0, sizeof(irsin)); 633 irsin.sin_family = AF_INET; 634 #ifdef BSD4_4 635 irsin.sin_len = sizeof(struct sockaddr_in); 636 #endif 637 memcpy(&irsin.sin_addr, &raddr, sizeof(irsin.sin_addr)); 638 return iruserok_sa(&irsin, sizeof(struct sockaddr_in), superuser, ruser, 639 luser); 640 } 641 642 /* 643 * 2nd and 3rd arguments are typed like this, to avoid dependency between 644 * unistd.h and sys/socket.h. There's no better way. 645 */ 646 int 647 iruserok_sa(raddr, rlen, superuser, ruser, luser) 648 const void *raddr; 649 int rlen; 650 int superuser; 651 const char *ruser, *luser; 652 { 653 struct sockaddr *sa; 654 struct stat sbuf; 655 struct passwd *pwd, pwres; 656 FILE *hostf; 657 uid_t uid; 658 gid_t gid; 659 int isvaliduser; 660 char pbuf[MAXPATHLEN]; 661 char pwbuf[1024]; 662 663 _DIAGASSERT(raddr != NULL); 664 _DIAGASSERT(ruser != NULL); 665 _DIAGASSERT(luser != NULL); 666 667 /*LINTED const castaway*/ 668 sa = (struct sockaddr *)(void *)raddr; 669 670 __rcmd_errstr = NULL; 671 672 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r"); 673 674 if (hostf) { 675 if (__ivaliduser_sa(hostf, sa, (socklen_t)rlen, luser, 676 ruser) == 0) { 677 (void)fclose(hostf); 678 return (0); 679 } 680 (void)fclose(hostf); 681 } 682 683 isvaliduser = -1; 684 if (__check_rhosts_file || superuser) { 685 686 if (getpwnam_r(luser, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0) 687 return (-1); 688 (void)strlcpy(pbuf, pwd->pw_dir, sizeof(pbuf)); 689 (void)strlcat(pbuf, "/.rhosts", sizeof(pbuf)); 690 691 /* 692 * Change effective uid while opening and reading .rhosts. 693 * If root and reading an NFS mounted file system, can't 694 * read files that are protected read/write owner only. 695 */ 696 uid = geteuid(); 697 gid = getegid(); 698 (void)setegid(pwd->pw_gid); 699 initgroups(pwd->pw_name, pwd->pw_gid); 700 (void)seteuid(pwd->pw_uid); 701 hostf = fopen(pbuf, "r"); 702 703 if (hostf != NULL) { 704 /* 705 * If not a regular file, or is owned by someone other 706 * than user or root or if writable by anyone but the 707 * owner, quit. 708 */ 709 if (lstat(pbuf, &sbuf) < 0) 710 __rcmd_errstr = ".rhosts lstat failed"; 711 else if (!S_ISREG(sbuf.st_mode)) 712 __rcmd_errstr = ".rhosts not regular file"; 713 else if (fstat(fileno(hostf), &sbuf) < 0) 714 __rcmd_errstr = ".rhosts fstat failed"; 715 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) 716 __rcmd_errstr = "bad .rhosts owner"; 717 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) 718 __rcmd_errstr = 719 ".rhosts writable by other than owner"; 720 else 721 isvaliduser = 722 __ivaliduser_sa(hostf, sa, (socklen_t)rlen, 723 luser, ruser); 724 725 (void)fclose(hostf); 726 } 727 (void)seteuid(uid); 728 (void)setegid(gid); 729 730 } 731 return (isvaliduser); 732 } 733 734 /* 735 * XXX 736 * Don't make static, used by lpd(8). We will be able to change the function 737 * into static function, when we bump libc major #. 738 * 739 * Returns 0 if ok, -1 if not ok. 740 */ 741 #ifdef notdef /*_LIBC*/ 742 static 743 #endif 744 int 745 __ivaliduser(hostf, raddr, luser, ruser) 746 FILE *hostf; 747 u_int32_t raddr; 748 const char *luser, *ruser; 749 { 750 struct sockaddr_in ivusin; 751 752 memset(&ivusin, 0, sizeof(ivusin)); 753 ivusin.sin_family = AF_INET; 754 #ifdef BSD4_4 755 ivusin.sin_len = sizeof(struct sockaddr_in); 756 #endif 757 memcpy(&ivusin.sin_addr, &raddr, sizeof(ivusin.sin_addr)); 758 return __ivaliduser_sa(hostf, (struct sockaddr *)(void *)&ivusin, 759 sizeof(struct sockaddr_in), luser, ruser); 760 } 761 762 #ifdef notdef /*_LIBC*/ 763 static 764 #endif 765 int 766 __ivaliduser_sa(hostf, raddr, salen, luser, ruser) 767 FILE *hostf; 768 struct sockaddr *raddr; 769 socklen_t salen; 770 const char *luser, *ruser; 771 { 772 register char *user, *p; 773 int ch; 774 char buf[MAXHOSTNAMELEN + 128]; /* host + login */ 775 const char *auser, *ahost; 776 int hostok, userok; 777 char *rhost = NULL; 778 int firsttime = 1; 779 char domain[MAXHOSTNAMELEN]; 780 781 getdomainname(domain, sizeof(domain)); 782 783 _DIAGASSERT(hostf != NULL); 784 _DIAGASSERT(luser != NULL); 785 _DIAGASSERT(ruser != NULL); 786 787 while (fgets(buf, sizeof(buf), hostf)) { 788 p = buf; 789 /* Skip lines that are too long. */ 790 if (strchr(p, '\n') == NULL) { 791 while ((ch = getc(hostf)) != '\n' && ch != EOF) 792 ; 793 continue; 794 } 795 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') { 796 *p = isupper((unsigned char)*p) ? 797 tolower((unsigned char)*p) : *p; 798 p++; 799 } 800 if (*p == ' ' || *p == '\t') { 801 *p++ = '\0'; 802 while (*p == ' ' || *p == '\t') 803 p++; 804 user = p; 805 while (*p != '\n' && *p != ' ' && 806 *p != '\t' && *p != '\0') 807 p++; 808 } else 809 user = p; 810 *p = '\0'; 811 812 if (p == buf) 813 continue; 814 815 auser = *user ? user : luser; 816 ahost = buf; 817 818 if (ahost[0] == '+') 819 switch (ahost[1]) { 820 case '\0': 821 hostok = 1; 822 break; 823 824 case '@': 825 if (firsttime) { 826 rhost = __gethostloop(raddr, salen); 827 firsttime = 0; 828 } 829 if (rhost) 830 hostok = innetgr(&ahost[2], rhost, 831 NULL, domain); 832 else 833 hostok = 0; 834 break; 835 836 default: 837 hostok = __icheckhost(raddr, salen, &ahost[1]); 838 break; 839 } 840 else if (ahost[0] == '-') 841 switch (ahost[1]) { 842 case '\0': 843 hostok = -1; 844 break; 845 846 case '@': 847 if (firsttime) { 848 rhost = __gethostloop(raddr, salen); 849 firsttime = 0; 850 } 851 if (rhost) 852 hostok = -innetgr(&ahost[2], rhost, 853 NULL, domain); 854 else 855 hostok = 0; 856 break; 857 858 default: 859 hostok = -__icheckhost(raddr, salen, &ahost[1]); 860 break; 861 } 862 else 863 hostok = __icheckhost(raddr, salen, ahost); 864 865 866 if (auser[0] == '+') 867 switch (auser[1]) { 868 case '\0': 869 userok = 1; 870 break; 871 872 case '@': 873 userok = innetgr(&auser[2], NULL, ruser, 874 domain); 875 break; 876 877 default: 878 userok = strcmp(ruser, &auser[1]) == 0; 879 break; 880 } 881 else if (auser[0] == '-') 882 switch (auser[1]) { 883 case '\0': 884 userok = -1; 885 break; 886 887 case '@': 888 userok = -innetgr(&auser[2], NULL, ruser, 889 domain); 890 break; 891 892 default: 893 userok = 894 -(strcmp(ruser, &auser[1]) == 0 ? 1 : 0); 895 break; 896 } 897 else 898 userok = strcmp(ruser, auser) == 0; 899 900 /* Check if one component did not match */ 901 if (hostok == 0 || userok == 0) 902 continue; 903 904 /* Check if we got a forbidden pair */ 905 if (userok == -1 || hostok == -1) 906 return -1; 907 908 /* Check if we got a valid pair */ 909 if (hostok == 1 && userok == 1) 910 return 0; 911 } 912 return -1; 913 } 914 915 /* 916 * Returns "true" if match, 0 if no match. 917 */ 918 static int 919 __icheckhost(raddr, salen, lhost) 920 struct sockaddr *raddr; 921 socklen_t salen; 922 const char *lhost; 923 { 924 struct addrinfo hints, *res, *r; 925 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 926 int error; 927 const int niflags = NI_NUMERICHOST; 928 929 _DIAGASSERT(raddr != NULL); 930 _DIAGASSERT(lhost != NULL); 931 932 h1[0] = '\0'; 933 if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0, 934 niflags) != 0) 935 return (0); 936 937 /* Resolve laddr into sockaddr */ 938 memset(&hints, 0, sizeof(hints)); 939 hints.ai_family = raddr->sa_family; 940 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 941 res = NULL; 942 error = getaddrinfo(lhost, "0", &hints, &res); 943 if (error) 944 return (0); 945 946 /* 947 * Try string comparisons between raddr and laddr. 948 */ 949 for (r = res; r; r = r->ai_next) { 950 h2[0] = '\0'; 951 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2), 952 NULL, 0, niflags) != 0) 953 continue; 954 if (strcmp(h1, h2) == 0) { 955 freeaddrinfo(res); 956 return (1); 957 } 958 } 959 960 /* No match. */ 961 freeaddrinfo(res); 962 return (0); 963 } 964 965 /* 966 * Return the hostname associated with the supplied address. 967 * Do a reverse lookup as well for security. If a loop cannot 968 * be found, pack the numeric IP address into the string. 969 */ 970 static char * 971 __gethostloop(raddr, salen) 972 struct sockaddr *raddr; 973 socklen_t salen; 974 { 975 static char remotehost[NI_MAXHOST]; 976 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 977 struct addrinfo hints, *res, *r; 978 int error; 979 const int niflags = NI_NUMERICHOST; 980 981 _DIAGASSERT(raddr != NULL); 982 983 h1[0] = remotehost[0] = '\0'; 984 if (getnameinfo(raddr, salen, remotehost, sizeof(remotehost), 985 NULL, 0, NI_NAMEREQD) != 0) 986 return (NULL); 987 if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0, 988 niflags) != 0) 989 return (NULL); 990 991 /* 992 * Look up the name and check that the supplied 993 * address is in the list 994 */ 995 memset(&hints, 0, sizeof(hints)); 996 hints.ai_family = raddr->sa_family; 997 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 998 hints.ai_flags = AI_CANONNAME; 999 res = NULL; 1000 error = getaddrinfo(remotehost, "0", &hints, &res); 1001 if (error) 1002 return (NULL); 1003 1004 for (r = res; r; r = r->ai_next) { 1005 h2[0] = '\0'; 1006 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2), 1007 NULL, 0, niflags) != 0) 1008 continue; 1009 if (strcmp(h1, h2) == 0) { 1010 freeaddrinfo(res); 1011 return (remotehost); 1012 } 1013 } 1014 1015 /* 1016 * either the DNS adminstrator has made a configuration 1017 * mistake, or someone has attempted to spoof us 1018 */ 1019 syslog(LOG_NOTICE, "rcmd: address %s not listed for host %s", 1020 h1, res->ai_canonname ? res->ai_canonname : remotehost); 1021 freeaddrinfo(res); 1022 return (NULL); 1023 } 1024